Compact Pulse Slicer for High-Power Submillimeter Waves

项目总结/摘要 复杂的生物大分子，如膜蛋白，在许多细胞和 生理过程和特定缺陷与许多已知的相关。决定他们的三个- 三维结构是结构生物学的主要目标之一，NIH投入了相当大的精力， 为实现这一目标提供资源。X射线晶体学和NMR光谱学是这种方法的主要来源。 信息.此外，电子顺磁共振（EPR）光谱，特别是偶极 光谱（PELDOR/DEER/RIDME）是精确距离信息的宝贵来源， 其他结构测定方法。然而，NMR由于其固有的低灵敏度而受到影响。 小核磁矩需要较长的采集时间才能获得足够的数据质量。结合 具有动态核极化（DNP）的NMR是克服这一限制的好方法，提高灵敏度， 将采集时间缩短了几个数量级。近年来，DNP增强NMR光谱 已经成为核磁共振波谱仪工具箱中不可或缺的一部分，因为该方法使研究人员能够 进行以前不可能的实验。 虽然DNP可以大幅提高NMR实验的灵敏度，但该方法的规模非常大。 不利地与磁场强度，导致较低的增强值在较高的magnice领域。 这对于基于样品的连续波（cw）辐射的所有DNP机制是共同的。脉冲DNP 另一方面，实验没有显示出这种行为。然而，创建/塑造 低功率（~ mW）的脉冲和放大它们（> 10-100 W）不起作用，因为缺乏高功率（~ mW）的脉冲。 功率/高频微波/太赫兹放大器。 在这个SBIR应用中，我们建议开发一个紧凑的交钥匙脉冲限幅器，以产生短，高， 通常用于DNP-NMR实验的cw源如回旋管的功率脉冲。的 即使对于非微波工程师，系统也将易于操作，并且可以容易地集成到现有系统中， 设置。 这种脉冲限幅器的成功开发将带来迫切需要的脉冲能力， 否则只能在CW模式下操作的系统。这将极大地推广该方法， 许多项目由美国国立卫生研究院资助。

Project Summary / Abstract Complex bio-macromolecules such as membrane proteins play crucial roles in many cellular and physiological processes and specific defects are associated with many known. Determining their three- dimensional structures is one of the main objectives in structural biology and the NIH devotes considerable resources towards this goal. X-ray crystallography and NMR spectroscopy are the major sources for such information. In addition, Electron Paramagnetic Resonance (EPR) spectroscopy, in particular dipolar spectroscopy (PELDOR/DEER/RIDME) is a valuable source for accurate distance information to complement other methods for structure determination. However, NMR suffers from an inherently low sensitivity due to the small nuclear magnetic moment. Long acquisition times are required to achieve sufficient data quality. Combining NMR with Dynamic Nuclear Polarization (DNP) is a great way to overcome this limit, boosting sensitivity and shortening acquisition times by several orders of magnitude. In recent years DNP-enhanced NMR spectroscopy has become an integral part of the NMR spectroscopists toolbox, because the method enables researchers to perform experiments that were previously not possible. While DNP can increase the sensitivity of an NMR experiment drastically, the methodology scales very unfavorably with the magnetic field strength, leading to lower enhancement values at higher magntice fields. This is common to all DNP mechanisms based on continuous wave (cw) radiation of the sample. Pulsed DNP experiments on the other hand do not show this behavior. However, the common approach of creating/shaping pulses at low powers (~ mW) and amplifying them (> 10-100 W) does not work because of the lack of high- power/high-frequency microwave/THz amplifiers. In this SBIR application we propose to develop a compact, turn-key pulse slicer to generate short, high- power pulses from cw sources such as gyrotrons, that are commonly used in DNP-NMR experiments. The system will be easy to operate even for non-microwave engineers and can be readily integrated into existing setups. The successful development of this pulse slicer will bring desperately needed pulse capabilities to systems that otherwise can only be operated in cw mode. This will greatly proliferate the method and is of large interest to many projects funded by the U.S. National Institutes of Health.